Home power lines usually use a single-phase three-wire system having first and second “hot” lines L1, L2 and a neutral that sends power to each home from a distribution transformer. Usually, several homes share one distribution transformer. Power lines L1 and L2 are normally coupled together (and usually coupled to neighbors) via the distribution transformer. Power line communication (PLC) networks utilize the existing power lines in order to facilitate computer networking (or networking of other appliances such as audio/video equipment). In one example, networks using the HomePlug® standard are used for achieving PLC communication. Since such networks interconnect devices using existing power outlets, information traveling over the power line may be accessible by neighbors or others tapping into the power line outside the home. If filtering is installed to prevent data from traveling outside the home, the two lines L1 and L2 may be isolated from each other.
In the case of global communication between lines L1 and L2, the signal may travel a long distance and get attenuated. Although attenuation in global communication is often negligible, sometimes it is not and thus it requires high transmission power, which would cause interference to other electronic products. This basic problem is addressed in U.S. patent application Ser. No. 11/297,528, the parent of the present application.
Powerline Communication (PLC) is expected to be used as a backbone of home networking. As of this writing, the second generation PLC standard is under discussion and will soon be finalized. The second generation PLC under discussion is a 200 Mbps class network. The actual payload rate, however, is 50 to 60 Mbps. This second generation is being proposed to simultaneously carry a few of MPEG-HD streams. Although the second generation PLC meets the present bandwidth requirements, bandwidth needs are likely to be ever increasing and more bandwidth will be required when HDTV streaming becomes common.